Cloudanix VulnDB

CVE-2025-39833

None

CVSS

—

EPSS

0.1%

Published

Sep 16, 2025

CISA due date

—

Cloudanix analysis

Monitor only SSVC: Track

A small driver cleanup issue in Linux can create warning messages when the driver is removed, but does not allow attackers to take control or access data.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Theoretical
Impact
Other
Component
OS kernel
Class
Other
Remediation
Patch
Effort
Low
Patch risk
None

What it actually does

Uninitialized timer in hfcpci module triggers debug object assert warning (ODEBUG) during module unload when __timer_delete_sync is called on a timer_list that was never initialized.

Why it matters to the business

Kernel warnings appear during driver removal on systems using the hfcpci module, potentially increasing log noise, complicating diagnostics, and affecting perceived system stability in environments with frequent module loading/unloading.

How an attack unfolds

An attacker would need local access to load and unload the hfcpci module; the issue manifests only as a warning during cleanup with no code execution, privilege escalation, or data access path.

How to fix it

Update the Linux kernel to commit 43fc5da8133badf17f5df250ba03b9d882254845 or later; for affected Debian packages update sane-backends to 1.0.11-1. Rebuild and reload the hfcpci module after applying the fix that initializes the timer via DEFINE_TIMER and switches to mod_timer.

How to confirm the fix worked

Confirm the fix by checking the kernel source for DEFINE_TIMER(hfc_tl, ...) in hfcpci and attempting module unload; verify absence of the ODEBUG warning in dmesg. Check package versions against the listed fixed releases.

Typical attack path

  1. Load hfcpci module without proper timer initialization path
  2. Trigger module unload via rmmod or system shutdown
  3. Observe ODEBUG warning in kernel logs from debug_object_assert_init

How to detect it

Search kernel logs for the exact ODEBUG assert_init message referencing timer_list and hfcpci during rmmod events; no remote or persistent artifacts exist.

What your security team should do

  • Prioritize kernel update on systems exposing the hfcpci driver within the next maintenance window due to 406 days since publication
  • Audit module load/unload scripts and initramfs for hfcpci usage
  • Monitor EPSS trend (currently stable near 0.0015) and re-evaluate if new exploit code appears

The record

In the Linux kernel, the following vulnerability has been resolved: mISDN: hfcpci: Fix warning when deleting uninitialized timer With CONFIG_DEBUG_OBJECTS_TIMERS unloading hfcpci module leads to the following splat: [ 250.215892] ODEBUG: assert_init not available (active state 0) object: ffffffffc01a3dc0 object type: timer_list hint: 0x0 [ 250.217520] WARNING: CPU: 0 PID: 233 at lib/debugobjects.c:612 debug_print_object+0x1b6/0x2c0 [ 250.218775] Modules linked in: hfcpci(-) mISDN_core [ 250.219537] CPU: 0 UID: 0 PID: 233 Comm: rmmod Not tainted 6.17.0-rc2-g6f713187ac98 #2 PREEMPT(voluntary) [ 250.220940] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 250.222377] RIP: 0010:debug_print_object+0x1b6/0x2c0 [ 250.223131] Code: fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 4f 41 56 48 8b 14 dd a0 4e 01 9f 48 89 ee 48 c7 c7 20 46 01 9f e8 cb 84d [ 250.225805] RSP: 0018:ffff888015ea7c08 EFLAGS: 00010286 [ 250.226608] RAX: 0000000000000000 RBX: 0000000000000005 RCX: ffffffff9be93a95 [ 250.227708] RDX: 1ffff1100d945138 RSI: 0000000000000008 RDI: ffff88806ca289c0 [ 250.228993] RBP: ffffffff9f014a00 R08: 0000000000000001 R09: ffffed1002bd4f39 [ 250.230043] R10: ffff888015ea79cf R11: 0000000000000001 R12: 0000000000000001 [ 250.231185] R13: ffffffff9eea0520 R14: 0000000000000000 R15: ffff888015ea7cc8 [ 250.232454] FS: 00007f3208f01540(0000) GS:ffff8880caf5a000(0000) knlGS:0000000000000000 [ 250.233851] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 250.234856] CR2: 00007f32090a7421 CR3: 0000000004d63000 CR4: 00000000000006f0 [ 250.236117] Call Trace: [ 250.236599] <TASK> [ 250.236967] ? trace_irq_enable.constprop.0+0xd4/0x130 [ 250.237920] debug_object_assert_init+0x1f6/0x310 [ 250.238762] ? __pfx_debug_object_assert_init+0x10/0x10 [ 250.239658] ? __lock_acquire+0xdea/0x1c70 [ 250.240369] __try_to_del_timer_sync+0x69/0x140 [ 250.241172] ? __pfx___try_to_del_timer_sync+0x10/0x10 [ 250.242058] ? __timer_delete_sync+0xc6/0x120 [ 250.242842] ? lock_acquire+0x30/0x80 [ 250.243474] ? __timer_delete_sync+0xc6/0x120 [ 250.244262] __timer_delete_sync+0x98/0x120 [ 250.245015] HFC_cleanup+0x10/0x20 [hfcpci] [ 250.245704] __do_sys_delete_module+0x348/0x510 [ 250.246461] ? __pfx___do_sys_delete_module+0x10/0x10 [ 250.247338] do_syscall_64+0xc1/0x360 [ 250.247924] entry_SYSCALL_64_after_hwframe+0x77/0x7f Fix this by initializing hfc_tl timer with DEFINE_TIMER macro. Also, use mod_timer instead of manual timeout update.

Affected packages

Ecosystem Package Introduced Fixed
Chainguard hyperv-daemons-6.12 0 6.12.60-r3
Chainguard linux-aws-6.12-boot-installed 0 6.12.60-r2
Chainguard linux-aws-6.12-fips-boot-installed 0 6.12.60-r2
Chainguard linux-aws-6.12-headers 0 6.12.60-r2
Chainguard linux-aws-6.12-modules 0 6.12.60-r2
Chainguard linux-azure-6.12-boot-installed 0 6.12.60-r4
Chainguard linux-azure-6.12-fips-boot-installed 0 6.12.60-r3
Chainguard linux-azure-6.12-headers 0 6.12.60-r3
Chainguard linux-azure-6.12-modules 0 6.12.60-r4
Chainguard linux-gcp-6.12-boot-installed 0 6.12.60-r2
Chainguard linux-gcp-6.12-fips-boot-installed 0 6.12.60-r2
Chainguard linux-gcp-6.12-headers 0 6.12.60-r2
Chainguard linux-gcp-6.12-modules 0 6.12.60-r2
Chainguard linux-qemu-6.12-boot-installed 0 6.12.63-r0
Chainguard linux-qemu-6.12-fips-boot-installed 0 6.12.63-r0
Chainguard linux-qemu-6.12-headers 0 6.12.63-r0
Chainguard linux-qemu-6.12-modules 0 6.12.63-r0
Chainguard linux-vmware-6.12 0 6.12.67-r0
Chainguard linux-vmware-6.12-boot-installed 0 6.12.63-r0
Chainguard linux-vmware-6.12-fips-boot-installed 0 6.12.63-r0
Chainguard linux-vmware-6.12-headers 0 6.12.63-r0
Chainguard linux-vmware-6.12-modules 0 6.12.63-r0
Debian:11 linux 0 No fix
Debian:12 linux 0 No fix
Debian:13 linux 0 No fix
Debian:14 linux 0 6.16.5-1
Linux Kernel 2.6.29 6.16.5
SUSE:Linux Enterprise High Availability Extension 15 SP6 kernel-default 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise High Availability Extension 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Live Patching 12 SP5 kernel-default 0 4.12.14-122.275.1
SUSE:Linux Enterprise Live Patching 12 SP5 kgraft-patch-SLE12-SP5_Update_73 0 1-8.3.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-default 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6-RT_Update_16 0 1-150600.1.3.1
SUSE:Linux Enterprise Live Patching 15 SP6 kernel-livepatch-SLE15-SP6_Update_16 0 1-150600.13.3.1
SUSE:Linux Enterprise Live Patching 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Live Patching 15 SP7 kernel-livepatch-SLE15-SP7_Update_6 0 1-150700.15.3.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-64kb 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-default-base 0 6.4.0-150600.23.73.1.150600.12.32.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-source 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6 kernel-zfcpdump 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-64kb 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-default-base 0 6.4.0-150700.53.22.1.150700.17.15.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-source 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Basesystem 15 SP7 kernel-zfcpdump 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-docs 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-obs-build 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-source 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Development Tools 15 SP6 kernel-syms 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7 kernel-docs 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7 kernel-obs-build 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7 kernel-source 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7 kernel-syms 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Legacy 15 SP6 kernel-default 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Module for Legacy 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-azure 0 6.4.0-150600.8.52.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-source-azure 0 6.4.0-150600.8.52.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP6 kernel-syms-azure 0 6.4.0-150600.8.52.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP7 kernel-azure 0 6.4.0-150700.20.18.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP7 kernel-source-azure 0 6.4.0-150700.20.18.1
SUSE:Linux Enterprise Module for Public Cloud 15 SP7 kernel-syms-azure 0 6.4.0-150700.20.18.1
SUSE:Linux Enterprise Server 12 SP5-LTSS kernel-default 0 4.12.14-122.275.1
SUSE:Linux Enterprise Server 12 SP5-LTSS kernel-source 0 4.12.14-122.275.1
SUSE:Linux Enterprise Server 12 SP5-LTSS kernel-syms 0 4.12.14-122.275.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-default 0 4.12.14-122.275.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-source 0 4.12.14-122.275.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-syms 0 4.12.14-122.275.1
SUSE:Linux Enterprise Workstation Extension 15 SP6 kernel-default 0 6.4.0-150600.23.73.1
SUSE:Linux Enterprise Workstation Extension 15 SP7 kernel-default 0 6.4.0-150700.53.22.1
SUSE:Real Time Module 15 SP6 kernel-rt 0 6.4.0-150600.10.55.1
SUSE:Real Time Module 15 SP6 kernel-rt_debug 0 6.4.0-150600.10.55.1
SUSE:Real Time Module 15 SP6 kernel-source-rt 0 6.4.0-150600.10.55.1
SUSE:Real Time Module 15 SP6 kernel-syms-rt 0 6.4.0-150600.10.55.1
openSUSE:Leap 15.6 dtb-aarch64 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-64kb 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-azure 0 6.4.0-150600.8.52.1
openSUSE:Leap 15.6 kernel-debug 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-default 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-default-base 0 6.4.0-150600.23.73.1.150600.12.32.1
openSUSE:Leap 15.6 kernel-docs 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-kvmsmall 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-obs-build 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-obs-qa 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-rt 0 6.4.0-150600.10.55.1
openSUSE:Leap 15.6 kernel-rt_debug 0 6.4.0-150600.10.55.1
openSUSE:Leap 15.6 kernel-source 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-source-azure 0 6.4.0-150600.8.52.1
openSUSE:Leap 15.6 kernel-source-rt 0 6.4.0-150600.10.55.1
openSUSE:Leap 15.6 kernel-syms 0 6.4.0-150600.23.73.1
openSUSE:Leap 15.6 kernel-syms-azure 0 6.4.0-150600.8.52.1
openSUSE:Leap 15.6 kernel-syms-rt 0 6.4.0-150600.10.55.1
openSUSE:Leap 15.6 kernel-zfcpdump 0 6.4.0-150600.23.73.1
openSUSE:Leap 16.0 dtb-aarch64 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-64kb 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-default 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-default-base 0 6.12.0-160000.6.1.160000.2.4
openSUSE:Leap 16.0 kernel-docs 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-kvmsmall 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-obs-build 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-obs-qa 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-rt 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-source 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-syms 0 6.12.0-160000.6.1
openSUSE:Leap 16.0 kernel-zfcpdump 0 6.12.0-160000.6.1

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